Hi,
I'm modeling hypervelocity impact (2.22 km/s tungsten carbide sphere on HSLA-100 steel) with coupled thermal-structural analysis using S-ALE (Structured ALE) mesh.
Initial Attempt & Issue:
I first tried the implicit thermal solver using:
- *CONTROL_SOLUTION (Thermal-Structural Analysis)
- *CONTROL_THERMAL_NONLINEAR
- *CONTROL_THERMAL_SOLVER
- *CONTROL_THERMAL_TIMESTEP
However, I observed physically unrealistic temperature rates (dT/dt on the order of billions of °K), which is physically impossible. I switched to the Explicit Thermal Solver (*CONTROL_EXPLICIT_THERMAL_* cards) as an alternative, but encountered a fatal initialization error.
Current Error:
```
forrtl: severe (164): Program Exception - integer divide by zero
Image PC Routine Line Source
lsdyna_mpp_dp_imp 00007FF731E6B4CC XPLCTH_INIT 1148 dyn20x.F
...
```
The crash occurs during initialization (`XPLCTH_INIT`), suggesting a division by zero in the thermal data setup.
Specific Questions:
1. Explicit Thermal Setup with S-ALE:
For cards like `*DATABASE_ALE`, `*CONTROL_EXPLICIT_THERMAL_INITIAL`, and `*CONTROL_EXPLICIT_THERMAL_OUTPUT`, the manual states SETID can be left blank for "all parts," but LS-PrePost/LS-DYNA requires an integer. Since S-ALE mesh elements are generated internally at runtime (not predefined in `*ELEMENT_SHELL`), I cannot reference them via traditional `*SET_SHELL_LIST`.
- How do I properly define SETID for S-ALE domains in these cards? Should I use `*SET_MULTI_MATERIAL_GROUP` instead?
2. Phase Change Modeling:
My material definition includes `*MAT_THERMAL_ISOTROPIC_PHASE_CHANGE` for the steel target (solid-to-liquid). Does the Explicit Thermal Solver support phase change energy (latent heat), or is this capability restricted to the implicit thermal solver? If supported, are there specific considerations for S-ALE multi-material groups?
3. Divide-by-Zero Cause:
The error trace points to `XPLCTH_INIT` (dyn20x.F:1148). This typically indicates zero thermal mass (density × specific heat) in a thermal part definition. Given that my vacuum/void material (`*MAT_ALE_VACUUM`) has near-zero thermal properties, could this be triggering the crash? Should vacuum regions be excluded from the thermal solver via `*SET_PART_LIST`, or is there a minimum non-zero thermal density requirement?
Model Context:
- 2D Axisymmetric S-ALE mesh (fine resolution)
- 3 ALE Multi-Material Groups: HSLA-100 Steel, Tungsten Carbide, Vacuum
- Thermal properties defined via *MAT_THERMAL_ISOTROPIC and *MAT_THERMAL_ISOTROPIC_PHASE_CHANGE
- Using MPP R14.1.1 on Windows
Keyword file attached for reference:
https://buffalo.box.com/s/y7rz3bqg4xsvuir6z94b50mcg2g3jp1s
Any guidance on proper explicit thermal initialization with S-ALE and phase change setup would be greatly appreciated.
Thanks,
Amrith